Imaging system including beam guiding element having high solarization resistance in the blue spectral range

Abstract

An imaging system, includes: a laser light source having a wavelength from 380 nm to 490 nm; and a beam guidance element, the laser light source configured for generating an average surface power density of more than 10 W/cm2, the beam guidance element including a glass which has a quality factor F(436 nm)=S(436 nm)*(Abs0(436 nm)+Abs1(436 nm))/k, wherein S(436 nm) is a thermality at a wavelength of 436 nm, Abs1(436 nm) is an additional absorbance in comparison to Abs0(436 nm) at a wavelength of 436 nm after an irradiation with a power density of 345 W/cm2 for 72 hours with a laser light having a wavelength of 455 nm, Abs0(436 nm) is an absorbance at a wavelength of 436 nm of a sample having a thickness of 100 mm without the irradiation, k is the thermal conductivity, and the quality factor F(436 nm) is <15 ppm/W.

What is claimed is: 
     
         1 . An imaging system, comprising:
 at least one laser light source B having a wavelength λ B  in a spectral range from 380 nm to 490 nm; and   a beam guidance element, the at least one laser light source B being configured for generating, in at least one point of the beam guidance element, an average surface power density of more than 10 W/cm 2 , the beam guidance element including a glass which has a quality factor F(436 nm)=S(436 nm)*(Abs 0 (436 nm)+Abs 1 (436 nm))/k, wherein S(436 nm) is a thermality at a wavelength of 436 nm, Abs 1 (436 nm) is an additional absorbance in comparison to Abs 0 (436 nm) at a wavelength of 436 nm of a sample having a thickness of 100 mm after an irradiation with a power density of 345 W/cm 2  for 72 hours with a laser light having a wavelength of 455 nm, Abs 0 (436 nm) is an absorbance at a wavelength of 436 nm of a sample having a thickness of 100 mm without the irradiation, k is the thermal conductivity, and the quality factor F(436 nm) is <15 ppm/W.   
     
     
         2 . The imaging system according to  claim 1 , wherein the at least one laser light source B is a diode laser. 
     
     
         3 . The imaging system according to  claim 1 , wherein the beam guidance element is a prism. 
     
     
         4 . The imaging system according to  claim 1 , wherein the at least one laser light source is configured for generating, in the at least one point of the beam guidance element, an average surface power density of 20 W/cm 2  to 300 W/cm 2 . 
     
     
         5 . The imaging system according to  claim 1 , wherein S(436 nm), S(546 nm), and S(644 nm) are at most 50 ppm/K. 
     
     
         6 . The imaging system according to  claim 1 , wherein Abs 0 (436 nm), Abs 0 (546 nm), and Abs 0 (644 nm) are less than 0.01/cm. 
     
     
         7 . The imaging system according to  claim 1 , wherein Abs 1 (436 nm), Abs 1 (546 nm), and Abs 1 (644 nm) are less than 0.009/cm. 
     
     
         8 . The imaging system according to  claim 1 , wherein the thermal conductivity k is more than 0.005 W/(cm*K). 
     
     
         9 . The imaging system according to  claim 1 , wherein an average do/dT at a wavelength of at least one of 436 nm, 546 nm, and 644 nm in a temperature range from 20° C. to 40° C. is in a range from 0.1 to 8.0 ppm/K. 
     
     
         10 . The imaging system according to  claim 1 , wherein the imaging system is configured for being used in a projector or in a materials processing. 
     
     
         11 . An imaging system, comprising:
 at least one laser light source B having a wavelength λ B  in a spectral range from 380 nm to 490 nm;   at least one laser light source G having a wavelength λ G  in a spectral range from >490 nm to 585 nm;   at least one laser light source R having a wavelength λ R  in a spectral range from >585 nm to 750 nm; and   a beam guidance element, the laser light source B, the laser light source G, and the laser light source R being configured for generating, in at least one point of the beam guidance element, an average surface power density of more than 10 W/cm 2 , the beam guidance element including a glass which has an induced absorbance Abs 1 (RGB)=Abs 1 (436 nm)+Abs 1 (546 nm)+Abs 1 (644 nm), wherein Abs 1 (RGB) is <0.03/cm.   
     
     
         12 . A beam guidance element, comprising:
 a glass which has at least one of the following properties:
 (a) a quality factor F(436 nm)=S(436 nm)*(Abs 0 (436 nm)+Abs 1 (436 nm))/k, wherein F(436 nm) is <15 ppm/W; 
 (b) a quality factor F(RGB)=F(436 nm)+F(546 nm)+F(644 nm)=S(436 nm)*(Abs 0 (436 nm)+Abs 1 (436 nm))/k+S(546 nm)*(Abs 0 (546 nm)+Abs 1 (546 nm))/k+S(644 nm)*(Abs 0 (644 nm)+Abs 1 (644 nm))/k, wherein F(RGB) is <40 ppm/W; 
 (c) an induced absorbance Abs 1 (436 nm)<0.01/cm; and 
 (d) an induced absorbance Abs 1 (RGB)=Abs 1 (436 nm)+Abs 1 (546 nm)+Abs 1 (644 nm), wherein Abs 1 (RGB) is <0.03/cm. 
   
     
     
         13 . The beam guidance element according to  claim 12 , wherein the beam guidance element is selected from at least one of lenses, prisms, aspheres, plane plates, freeforms, fast axis collimators, and light-guiding rods. 
     
     
         14 . A glass, comprising:
 at least one of the following properties:
 (a) a quality factor F(436 nm)=S(436 nm)*(Abs 0 (436 nm)+Abs 1 (436 nm))/k, wherein F(436 nm) is <15 ppm/W; 
 (b) a quality factor F(RGB)=F(436 nm)+F(546 nm)+F(644 nm)=S(436 nm)*(Abs 0 (436 nm)+Abs 1 (436 nm))/k+S(546 nm)*(Abs 0 (546 nm)+Abs 1 (546 nm))/k+S(644 nm)*(Abs 0 (644 nm)+Abs 1 (644 nm))/k, wherein F(RGB) is <40 ppm/W; 
 (c) an induced absorbance Abs 1 (436 nm)<0.01/cm; and 
 (d) an induced absorbance Abs 1 (RGB)=Abs 1 (436 nm)+Abs 1 (546 nm)+Abs 1 (644 nm), wherein Abs 1 (RGB) is <0.03/cm.